Various baseboards equipped with signal processing modules, such as microcomputers, are commercially available. Such baseboards are connected to extension modules that have specific functions to achieve various objects, such as signal output, control, and other operations.
In this specification, a signal processing module primarily functions as a computer and may be a computer including a central processing unit (CPU) as a microprocessor or any other device that practically functions as a microcomputer through the use of ICs, such as an ASIC or an FPGA, or any specialized IC.
In this specification, a baseboard refers to a circuit board equipped with a signal processing module and connectable to an extension module for achieving specific functions, such as signal output, operation, or control, in accordance with an object. The baseboard may also include an indicator and/or an audio output terminal for indicating the operating state of the signal processing module.
FIG. 46 illustrates a conventional baseboard including a signal processing module or microcomputer. In FIG. 46, the baseboard 1 is equipped with a microprocessor 2 of the microcomputer and other essential circuit devices. The baseboard 1 has a source terminal+Vcc and a ground terminal GND for receiving a DC power from an external power source, a microphone jack 3 for receiving audio signals, audio-signal output terminals or speaker output terminals 5, a USB connector 4, and an LED for displaying the operating state of the microcomputer. The baseboard 1 also has a group 9 of input/output terminals that are primarily used as analog-signal input terminals, and another group 10 of communication input/output terminals that are used for communication with external units.
With reference to FIG. 46, the group 9 of analog-signal input/output terminals is disposed along the left edge of the baseboard 1 and parts of the top and bottom edges. As illustrated in FIG. 46, the group 9 of input/output terminals includes many triplets of terminals, each triplet consisting of three terminals, i.e., a ground terminal 6 to be connected to the ground, a power terminal 7 to be connected to a power terminal or input source+Vcc (=3.3 V), and a signal terminal 8. The ground terminals 6 are disposed closest to the edges of the baseboard 1, the power terminals 7 second closest, and the signal terminals 8 the furthest. All ground terminals 6 are electrically connected with the ground terminal GND, and all power terminals 7 are electrically connected with the source terminal+Vcc.
The microprocessor 2 receives signals from the signal terminals and processes the signals with software installed in advance. The group 10 of communication input/output terminals consists of pairs of terminals. At least one triplet or pair is selected from among the triplets of the analog-signal input/output terminals in the group 9 and the pairs of the communication input/output terminals in the group 10 and is electrically connected to an extension module via lead lines to achieve a specific function through cooperation of the baseboard 1 and the extension module.
FIG. 47 illustrates an example connection of a conventional baseboard equipped with a microcomputer and an extension module. The baseboard represented by reference numeral 11 in FIG. 47 has a different specification from that of the baseboard 1 illustrated in FIG. 46. The baseboard 11 is equipped with a microprocessor 12, and an appropriate number of connectors 13 are disposed along the edges of the baseboard 11. Some of the connectors 13 are to be connected to the ground and the power source, and the others connect to the microprocessor 12 to transmit/receive signals to/from the microprocessor 12.
The baseboard 11 is disposed over a breadboard 14. As well known, a breadboard 14 is a solderless board that allows the construction of an electronic circuit by merely plugging in various electronic parts and jumper lines and is usually used for experiment, evaluation, and prototyping of circuits. The rectangular breadboard 14 has many ground terminal holes 15 connecting to a ground line and disposed in a straight line at a constant pitch along both longitudinal edges. Many source terminal holes 16 connecting to a source line are disposed parallel to the rows of the ground terminal holes 15 and define pairs with the respective ground terminal holes 15. The breadboard 14 has rows of ground terminal holes 15 and rows of power terminal holes 16 along both longitudinal sides. The area between these rows on both sides has a large number of terminal holes 17 arranged in a matrix at a constant pitch. The terminal holes 17 form rows in the transverse direction of the breadboard 14 or a direction orthogonal to the rows of ground terminal holes and the rows of source terminal holes. The terminal holes 17 in each row are electrically connected. The rows of terminal holes are arranged parallel to each other.
The breadboard 14 is equipped with an extension module 20, which is composed of a circuit having a specific function mounted on a circuit board. A plurality of terminal pins of the extension module 20 are fit into the terminal holes 17 in different rows aligned along the longitudinal direction of the breadboard 14. Thus, the terminal pins of the extension module 20 are electrically connected to the terminal holes 17 in different rows of terminal holes in the breadboard 14. The ground pin of the extension module 20 is inserted, so that one end of a jumper line 19 is fit into one of the electrically conductive terminal holes 17 in a single row. The other end of the jumper line 19 is fit into one of the ground terminal holes 15 to connect the ground pin of the extension module 20 to the ground line. Similarly, a source pin of the extension module 20 is inserted, so that an end of the jumper line 19 is fit into one of the electrically conductive terminal holes 17 in a single row. The other end of the jumper line 19 is fit into one of the source terminal holes 16 to connect the source pin of the extension module 20 to the source line.
One end of a lead line 18 is fit into one of the terminal holes 17 in a single row that is electrically connected to a signal terminal of the extension module 20, and the other end of the lead line 18 is connected to a predetermined one of the connectors 13 of the baseboard 11. In this way, the signal terminal of the extension module 20 is electrically connected to a predetermined terminal of the microprocessor 12 or a predetermined connection point of the baseboard 11. A plurality of lead lines 18 is provided. A plurality of connection points of the baseboard 11 is connected to a plurality of connection points of the extension module 20 via the connectors 13 of the baseboard 11, the lead lines 18, and the terminal holes 17 in the breadboard 14.
As described above, the structure for connecting a conventional baseboard and an extension module consist of lead lines. In the conventional baseboard illustrated in FIG. 46, first ends of lead lines are soldered to the terminals. Alternatively, lead lines are extracted from connectors fixed to the terminals, and second ends of the lead lines are soldered to or connected via connectors to the extension module.
A plurality of lead lines connecting the baseboard and the extension module complicates the structure and the connecting operation. Furthermore, a complicated operation of disconnection and reconnection of the lead lines will be required for a change in the specification, which may lead to faulty wiring.
The related art of the present invention includes the following inventions. Patent Literature 1 describes a system for part boards that electrically connects a stack of connection boards to a plurality of part boards disposed in a direction orthogonal to the connection boards by connecting a first group of contact devices disposed along the edges of the part boards and a second group of contact devices disposed along the edges of the connection boards. Patent Literature 1 only discloses the mechanical structure for directly connecting the connection boards and the part boards by engaging first and second contacts, which are equivalent to pins and jacks of a connector, but does not disclose a specific electrical connection.
Patent Literature 2 discloses a power source structure for a communication device. The structure has a support that is an assembly of multiple columns having a U-shaped cross-section and that accommodates a power source bus to increase the wiring area on the back side of the support, so as to increase the number of feeding cables to be connected and enhance the efficiency of the wiring operation. Patent Literature 2 has relevance to the present invention in the ease of wiring in the present invention but does not have direct relevance in the structure for connecting a baseboard equipped with a microcomputer and an extension module.
Patent Literature 3 discloses a data communication system connecting a plurality of devices with an SPI device. The system includes a communication manager adjusting serial communication between a mater device and slave devices. The serial communication to the slave devices is controlled by the communication manager on the basis of an appropriate physical protocol via communication interfaces. According to the invention described in Patent Literature 3, communication protocols may be switched among chip selecting signal lines to establish communication among the devices using the respective optimal communication protocols. Patent Literature 3, however, does not mention a structure for connecting a baseboard equipped with a microcomputer and an extension module.